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View Full Version : Rocker arm roller replacement!!!!! with pics!



86Shelby
07-27-2007, 08:53 PM
I finally got back the first sample of what should be a viable repair for the worn rollers on our rocker ams! I think this will work out alright. It is a slip-fit in the rocker, while the stock stuff is a press fit. This one is made of stainless steel, not sure of the alloy, hardness, etc. They are designed to use the rollers and needle bearings from 8V rockers. Let me know what you think.

There is NO pricing of this as of yet, so don't ask. I'm not trying to be snooty, I don't know what the sample peices I had made will cost me yet.:o

Anyway, on with the pics.

http://www.turbo-mopar.com/forums/photopost/data/500/medium/IMG_6671.JPG
http://www.turbo-mopar.com/forums/photopost/data/500/medium/IMG_6673.JPG
http://www.turbo-mopar.com/forums/photopost/data/500/medium/IMG_6678.JPG
http://www.turbo-mopar.com/forums/photopost/data/500/medium/IMG_6680.JPG
http://www.turbo-mopar.com/forums/photopost/data/500/medium/IMG_6670.JPG
http://www.turbo-mopar.com/forums/photopost/data/500/medium/IMG_6675.JPG

They are nice and close fitting to the side, so there is no worry of it contacting the head when installed.

http://www.turbo-mopar.com/forums/photopost/data/500/medium/IMG_6689.JPG

glhs727
07-27-2007, 09:08 PM
Great idea, I'd like to hear more!!!

Directconnection
07-27-2007, 09:23 PM
Good idea, but... #1) are you sure a slip fits is a better idea? Now the pin must rotate and the bore of the rocker is going to be a load carrying bearing surface. #2) SS is soft.

None of this may be a problem, but something to think about.

WOP'R
07-28-2007, 11:46 PM
i would like to know how much the pice once you find out...also any thoughts on making it out of chrome moly or something as hard/harder?

turbovanmanČ
07-29-2007, 03:55 AM
Nice.

I would do a few things. Either sell the pins by themselves, sell a modified rocker arm or modded customer one and knurl the one end so it doesn't rotate in the rocker arm, :thumb:

jay
07-29-2007, 04:01 AM
get em cryo treated too!

86Shelby
07-29-2007, 11:39 AM
I'll look into having the ends knurled to see if it's feasible. Pretty good idea there. This was just the prototype, the real thing will be made of a harder material.

turbovanmanČ
07-29-2007, 04:31 PM
I am not sure what material to use, I would just ask a metal place and tell them the intended application, they'll know for sure.

As for knurling yeah, I thought of maybe having a raised part but then that would take alot of machining. I honestly wouldn't have that setup so the pin can turn, I bet over time, it will wear out the rocker arm.

86Shelby
08-06-2007, 08:36 PM
Still researching the right metal to use. Some say 4340, other want 17CrNiMo6(supposed to be a little harder than 4340).

Those SS pins are good for...well....not much. :(

turbovanmanČ
08-07-2007, 05:53 PM
Those SS pins are good for...well....not much. :(


They look pretty, ;) :partywoot:

WOP'R
08-20-2007, 01:16 AM
any update?

86Shelby
08-20-2007, 11:29 AM
Not yet. Still waiting to get them back from being heat treated. We decided on 4340. After I get them back I still need to put the car back together and spare time is in short supply.

Turbo Joe
08-21-2007, 06:07 PM
:confused: so you heat treated the 4340 chromemoly? 4340 moly is way stronger than the rocker, and with the bearing being almost as wide as the pin, most of the load is spread pretty even across the pin. So are these pins gonna be availible as a repair kit? and when is someone gonna make some aftermarket rockers? 7075 or 4340 please?:eyebrows:

mech1nxh
08-21-2007, 06:57 PM
Very Nice!!

A thought here on the method of pin retention,
perhaps increase pin OD by .001-.0015 ?
(unsure of exact amount).
And freeze the pin, then assemble?

86Shelby
08-21-2007, 11:41 PM
so you heat treated the 4340 chromemoly?

Yes, we did. We found that untreated 4340 didn't quite have the hardness to serve as a roller bearing surface. Damn strong material, but not quite hard enough on the surface. They tested at 60 rockwell where most roller bearing surfaces are 60-65.

We thought about putting some pieces in an oven and others in a freezer, but there wouldn't be enough clearnace in the bearing for lubrication and free movement.

As far as if this will be offered as a replacement, we'll see. I'm going to run them for a while on my car, then dissassemble a few. I'm not going to offer them without testing the waters first.

turbovanmanČ
08-21-2007, 11:49 PM
Very Nice!!

A thought here on the method of pin retention,
perhaps increase pin OD by .001-.0015 ?
(unsure of exact amount).
And freeze the pin, then assemble?

That could work, my only negative would be the area is thin around there, it could maybe crack the pin hole?

86Shelby
08-22-2007, 01:24 AM
.001 isn't enough to be a press fit(or snug fit for that matter) in the rocker. Although .001 is enough to make the roller difficult to turn. We used the same OD shaft measurement as the shafts from brand new 8V rocker arms.

Chad and I went through 4 or 5 different shaft diameters trying to get a snug fit on the rocker and still let the needle bearings do thier job easily. There wasn't a better fit than the 8V shaft specs. Thank goodness that stainless wasn't horribly expensive.:amen:

86Shelby
08-22-2007, 01:31 AM
:and when is someone gonna make some aftermarket rockers? 7075 or 4340 please?:eyebrows:

I might work on that next. I'm hoping to be able to take some night courses for CAD and CNC machining at the local community college this fall....and they will rent time on the machines to students! Higher ratio billet rocker arms anyone??? ;)

2.216VTurbo
08-22-2007, 01:24 PM
I might work on that next. I'm hoping to be able to take some night courses for CAD and CNC machining at the local community college this fall....and they will rent time on the machines to students! Higher ratio billet rocker arms anyone??? ;)

Nah, who would want something like that:eyebrows: :evil: :lol: ?

turbovanmanČ
08-22-2007, 02:54 PM
I might work on that next. I'm hoping to be able to take some night courses for CAD and CNC machining at the local community college this fall....and they will rent time on the machines to students! Higher ratio billet rocker arms anyone??? ;)

I'm in unless the pricing is worth more than the engine, :(

86Shelby
08-22-2007, 05:01 PM
Eleventy billion dollars for a set, no less.:lol:

86Shelby
01-10-2008, 05:51 PM
Here's an update on the rocker repair after 500 miles of use. Good, bad & ugly, it's all here. When we designed them I didn't have any cams handy to notice that the cam journals don't ride centered in the cam bores. They sit off to one side. That caused some light interference issues between the cam journal and a rocker pin. The pin wore down the side of the cam journal a bit, but the pin was not harmed. Engine bearings are fine, but there was some damage to the oil pump due to the debris. To run all 16 modded rockers the cams will require some light machining on a lathe to make the needed clearance. I've attached a few pics to show what has happened. Since I am only running 6 modded rockers for the time being I am repositioning 3 of them so they will not contact the cam journals.

Untouched rocker pin.
http://i225.photobucket.com/albums/dd65/86Shelby/IMG_7358.jpg

Untouched cam journal.
http://i225.photobucket.com/albums/dd65/86Shelby/IMG_7354.jpg

This rocker pin contact the cam. No wear, though it is marked.
http://i225.photobucket.com/albums/dd65/86Shelby/IMG_7356.jpg

This cam journal took the brunt of the wear from the pin pictured above. Likely it won't affect the strength of the cam and I'll have it touched up later when it's repaired for reasons NOT related to the rocker pins.
http://i225.photobucket.com/albums/dd65/86Shelby/IMG_7351.jpg

After 500 miles there was no noticeable wear on the rockers themselves where the pins ride. The holes were not egg shaped or anything like that. The pins themselves still look great where the rollers ride; no pitting or scoring. I'll report more after a few thousand miles to see how things are holding up then.

turbovanmanČ
01-10-2008, 05:55 PM
Looks good. So what was the final method for the pin?

86Shelby
01-11-2008, 11:14 PM
So far it's 4140 steel. Hardened then polished to a mirror finish. Tack weld retaining clips on the end. I actualy ended up with only a portion of the clip welded on since the clip was very thin and tough to weld without simply melting it. No problems so far.